In my opinion Buchi makes the very best rotovaps. If someone is planning to buy the Buchi R 205 model I would suggest to buy the following equipment at the same time. The additional cost will not be that much.
Buchi V 805 vacuum controller
Buchi V 500 vacuum pump + Valve unit
The V 805 will make simple distillations and stripping of solvents practically automatic. But if you do some reading up on it you'll se that much much more can be done with it. Highly recommended!The V 500 is a very good and sturdy diaphragm pump, which can reach < 10 mbar.
The amount of cooling water running through the condensor can be kept at a minimum using Buchi's cooling water valve. The V 805 unit is connected with the cooling water valve along with two temperature sensors. One sensor is mesuring the temp of the water leaving the condensor and the other is measuring the temp of the condensate. The V 805 unit opens the coling water valve only when needed, thus keeping tap water requirements to a minimum.
Another option, which in my opinion is the best choise, is to buy a separate cooling/heating unit with a intergrated pump. Those can be bought second hand for $200-500. It is a device which can either heat or cool for example water. The temp range is usually -30 to 100°C.